"Macroevolution" has been observed too. There's direct genetic evidence, fossil evidence, morphological evidence, geographical evidence, etc.
No, that's known as the fallacy of the single cause.
To sum. First we had the fallacy of reverse ad hominem followed by the twin fallacies of equivocation and affirming the consequent. Now we add the fallacy of the single cause.
This is why I said, "Once again we see the multiplication of logical fallacies surrounding evolution. It is simply a consequence of and quite necessary to support that belief."